JP2014185023A - Carrier device and image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a carrier device and an image forming device, capable of suppressing generation of sound accompanying carriage.SOLUTION: An image forming device 10 has: a register roller 700 stopping a tip part of a sheet P and resuming movement of the tip part of the sheet P; a carrying roller 710 supplying the sheet P to the register roller 700; and a driven roller 720 driven by the carrying roller 710. The image forming device 10 carries the sheet P in a position between the carrying roller 710 and the driven roller 720, and the resister roller 700 such that the sheet P is formed with flexure, and also has attitude maintenance means 770 making the sheet P maintain an attitude formed with the flexure when a rear end part of the sheet P has passed through a contact part between the carrying roller 710 and the driven roller 720.

Description

  The present invention relates to a conveyance device and an image forming apparatus.

  Japanese Patent Application Laid-Open No. 2004-151867 discloses an automatic document feeder that is mounted on an image processing apparatus capable of reading a document image and automatically conveys a document placed on a document placement plate toward the image processing apparatus. A document conveyance path that guides the document to the image processing apparatus, and a document conveyance path that is provided in the document conveyance path, temporarily stops the document conveyed toward the image processing apparatus, and creates a predetermined amount of deflection at the leading edge of the document. The registration means, the rotation amount detection means for detecting the rotation amount of the registration means, and the rotation of the registration means are started at a relatively slow first peripheral speed in synchronism with the operation of the image processing apparatus. And a resist drive control means for rotating the registration means at a relatively high second peripheral speed in response to the rotation amount of the registration means detected by the step reaching a predetermined rotation amount. Feature Automatic document feeder for is described.

  Patent Document 2 includes a sheet feeding unit that accommodates a sheet and conveys the sheet, and a registration roller adjustment unit that conveys the sheet conveyed from the sheet feeding unit. The sheet is abutted against the registration roller adjustment unit, In a paper transporting apparatus that starts transporting paper again at a predetermined timing after giving a deflection, a buffering means is provided at a deflection forming portion of the paper, the buffering means is provided with a plurality of elastic sheet members, and one sheet A sheet conveying apparatus is described in which the leading end of the member is in contact with the antinode of the other sheet member at a predetermined angle.

  In Patent Document 3, a pickup roller that feeds a placed document, a separation roller that transports the delivered document, a registration roller that abuts against the document and temporarily stops the document and transports the document at a predetermined timing, In a document conveying apparatus having a driving means for moving each roller and a control means for controlling the driving means, a first acceleration for starting the pickup roller and the separation roller to drive them at a predetermined conveying speed, and the resist And a second acceleration for driving the roller to a predetermined conveyance speed, and the second acceleration is set slower than the first acceleration. .

JP-A-10-157882 JP 2003-252479 A Japanese Patent Laid-Open No. 2004-51275

  SUMMARY An advantage of some aspects of the invention is that it provides a conveyance device and an image forming apparatus that can suppress generation of sound accompanying conveyance.

  The present invention according to claim 1 is configured to stop the front end portion of the transport target object in a state where the rotation is stopped, and to resume the movement of the front end portion of the transport target object by starting the rotation to transport the transport target object. A conveying object between the supply member and a supply member that is disposed upstream of the conveying member in the conveying direction of the member and the conveying object, and that supplies the conveying object toward the conveying member The driven member that is disposed so as to be sandwiched, and the supply member and the driven member when a rear end portion of the conveyance object passes through a contact portion between the supply member and the driven member. And a posture maintaining means that maintains the posture having the deflection formed on the conveyance target at the position between the conveyance member and the conveyance target.

  According to a second aspect of the present invention, the posture maintaining means includes at least one of a separation member that separates the conveyance object from the driven member and a separation member that separates the conveyance object from the supply member. 1.

  According to a third aspect of the present invention, in the posture maintaining means, at least one of the driven member and the supply member when the rear end portion of the conveyance object passes through a contact portion between the supply member and the driven member. It is a conveying apparatus of Claim 1 or 2 which has a stop means to stop one side.

  The present invention according to claim 4 is the conveying apparatus according to any one of claims 1 to 3, wherein the posture maintaining means includes a friction coefficient reducing means for reducing a friction coefficient of the surface of the driven member.

  According to a fifth aspect of the present invention, there is provided an image forming unit for forming an image on a recording medium, and the image at the leading end of the recording medium by stopping the leading end of the recording medium in a stopped state and starting the rotation. A conveying member that resumes movement toward the forming unit and conveys the recording medium, and is arranged upstream of the conveying member in the conveying direction of the recording medium, and supplies the recording medium toward the conveying member A recording medium is sandwiched between the supply member and the supply member, a driven member that follows the supply member, and a rear end portion of a conveyance target is in contact with the supply member and the driven member A posture maintaining means for maintaining the conveyance object to maintain a posture having a deflection formed on the conveyance object at a position between the supply member and the driven member and the conveyance member when passing the section. Image formation It is the location.

  According to the first aspect of the present invention, it is possible to suppress the generation of sound associated with conveyance, as compared with the case where the present configuration is not provided.

  According to the second aspect of the present invention, the object to be conveyed can be easily separated from the driven member as compared with the case where the present configuration is not provided.

  According to this invention which concerns on Claim 3, compared with the case where it does not have this structure, the movement of the conveyance member rear-end part in the direction away from the contact part of a supply member and a driven member can be suppressed.

  According to the fourth aspect of the present invention, the movement of the rear end of the conveying member in the direction away from the contact portion between the supply member and the driven member can be suppressed as compared with the case where the present configuration is not provided.

  According to the fifth aspect of the present invention, it is possible to suppress the generation of sound due to conveyance, as compared with the case where the present configuration is not provided.

FIG. 3 is a diagram illustrating a cross section viewed from the front side of the image forming apparatus according to the first exemplary embodiment of the present invention. FIG. 2 is a diagram illustrating a cross section viewed from the front side of an image forming unit included in the image forming apparatus illustrated in FIG. 1. FIG. 2 is a diagram illustrating a conveyance member, a supply member, and a driven member included in the image forming apparatus illustrated in FIG. 1 and a configuration in the vicinity of these members. FIG. 6 is a diagram illustrating a conveyance member, a supply member, and a driven member included in an image forming apparatus according to a second embodiment of the present invention, and a configuration in the vicinity of these members. FIG. 5 is a diagram illustrating a supply member included in an image forming apparatus according to a second embodiment of the present invention and a configuration in the vicinity of the supply member, as viewed from the direction of arrows AA shown in FIG. It is a figure explaining the structure of the stop mechanism which the image forming apparatus which concerns on the 2nd Embodiment of this invention has. 6 is a flowchart illustrating an operation of an image forming apparatus according to a second embodiment of the present invention. It is a figure which shows the structure of the conveyance member which the image forming apparatus which concerns on the 3rd Embodiment of this invention, a supply member, a driven member, and these members vicinity. FIG. 9A is a first diagram illustrating a state of a sheet in an image forming apparatus according to a comparative example of the present invention, and FIG. 9A illustrates a state in which the rear end portion of the sheet passes through a contact portion between a supply member and a driven member. FIG. 9B shows the state of the paper after a certain time has elapsed from the time shown in FIG. 9A. FIG. 10A is a second diagram illustrating a state of a sheet in an image forming apparatus according to a comparative example of the present invention, and FIG. 10A is a time point when a rear end portion of the sheet passes through a contact portion between a supply member and a driven member. FIG. 10B shows the state of the paper after a certain time has elapsed from the time shown in FIG. 10A.

Next, embodiments for carrying out the present invention will be described with reference to the drawings.
FIG. 1 shows an image forming apparatus 10 according to the first embodiment of the present invention. The image forming apparatus 10 includes an image forming apparatus main body 12, and the controller 20, the communication device 22, the image forming unit 100, the optical scanning device 260, and the paper feeding device 400 are disposed in the image forming apparatus main body 12. . A document reading device 500 is mounted on the upper part of the image forming apparatus main body 12, and a sheet on which image formation has been completed is discharged out of the image forming apparatus main body 12 on the right side surface of the image forming apparatus main body 12. A discharge hole 14 is formed. Here, the paper is used as a transport object that is a transport target, and is also used as a recording medium on which an image is recorded.

  In addition, a discharge tray 16 on which a sheet discharged from the image forming apparatus main body 12 through the discharge hole 14 is placed is mounted on the right side surface of the image forming apparatus main body 12. In addition, a conveyance path 600 that is a conveyance path for conveying a sheet is formed in the image forming apparatus main body 12. The image forming apparatus 10 has a printer function for printing image data received from a computer terminal or the like connected via a network or the like, and also functions as a scanner, a copier, and a facsimile. It is what has.

  The document reader 500 is placed on a glass plate 502 on which a document D on which an image to be read is written is placed, a cover member 504 that presses the document D against the glass plate 502, and the glass plate 502. And a reading optical unit 510 that reads an image written on the document D. The reading optical unit 510 is configured to illuminate a document D placed on the glass plate 502 with a light source 512 and read a reflected light image from the document D with an image reading element 514 through a mirror group and a lens. Yes. Image data read by the document reading apparatus 500 is output to the controller 20.

  The controller 20 determines in advance such as shading correction, document position shift correction, gamma correction, frame erasing, color / movement editing, and the like for image data read by the document reading device 500 or image data received from a computer terminal or the like. The obtained image processing is performed.

  The communication device 22 receives image data from, for example, a computer terminal and outputs the received image data to the controller 20.

  The image forming unit 100 forms an image based on the image data output from the controller 20, and includes, for example, four image forming units 110Y, an image forming unit 110M, an image forming unit 110C, and an image forming unit 110K. Furthermore, a transfer device 300 is provided. The image forming unit 110M, the image forming unit 110C, and the image forming unit 110K are each used for forming a yellow image, used for forming a magenta image, and used for forming a cyan image. , Used to form a black image. Further, the image forming unit 110Y, the image forming unit 110M, the image forming unit 110C, and the image forming unit 110K each include a photoconductive drum 112Y, a photoconductive drum 112M, a photoconductive drum 112C, and a photoconductive drum 112K.

  Each of the photosensitive drum 112Y, the photosensitive drum 112M, the photosensitive drum 112C, and the photosensitive drum 112K is used as an image holding body that holds a toner image. Details of the image forming unit 110Y, the image forming unit 110M, the image forming unit 110C, and the image forming unit 110K will be described later.

  The optical scanning device 260 is a device that scans light based on image data output from the controller 20, and includes, for example, four optical scanning units 262Y, an optical scanning unit 262M, an optical scanning unit 262C, and an optical scanning unit 262K. . The optical scanning unit 262Y, the optical scanning unit 262M, the optical scanning unit 262C, and the optical scanning unit 262K irradiate light to the photosensitive drum 112Y, the photosensitive drum 112M, the photosensitive drum 112C, and the photosensitive drum 112K, respectively. And used as a latent image forming apparatus for forming an electrostatic latent image.

  The transfer device 300 includes an intermediate transfer belt 302. The intermediate transfer belt 302 is in contact with the photosensitive drum 112Y, the photosensitive drum 112M, the photosensitive drum 112C, and the photosensitive drum 112K, and the photosensitive drum 112Y, the photosensitive drum 112M, the photosensitive drum 112C, and the photosensitive drum 112K, for example. The toner images are transferred from the photosensitive drum 112Y, the photosensitive drum 112M, the photosensitive drum 112C, and the photosensitive drum 112K while moving with a difference in peripheral speed.

  The intermediate transfer belt 302 is band-shaped and endless, and is formed, for example, by forming a flexible synthetic resin film such as polyimide in a band shape and connecting both ends of the formed synthetic resin film by welding or the like. Can be used.

  Further, the intermediate transfer belt 302 is wound around the support roller 310, the support roller 312, the support roller 314, the support roller 316, the support roller 318, and the support roller 320, which are, for example, six support rollers. Is supported. At least one of the six support rollers is used as a drive transmission member that transmits drive to the intermediate transfer belt 302. In this embodiment, the support roller 310 is used as a drive transmission member, and the intermediate transfer belt is moved in the direction of arrow a by rotating the support roller 310 in response to drive transmission from a drive motor (not shown). Driven to rotate.

  In addition, the transfer device 300 includes, for example, four primary transfer rollers 330Y, a primary transfer roller 330M, a primary transfer roller 330C, and a primary transfer roller 330K, which are primary transfer rollers. The primary transfer roller 330Y, the primary transfer roller 330M, the primary transfer roller 330C, and the primary transfer roller 330K are respectively an intermediate transfer belt from the photosensitive drum 112Y, the photosensitive drum 112M, the photosensitive drum 112C, and the photosensitive drum 112K. It is used as a transfer member (primary transfer member) to which a transfer voltage for transferring a toner image is applied to 302.

  The transfer device 300 includes a secondary transfer roller 390. The secondary transfer roller 390 is used as a transfer member (secondary transfer member) for transferring a toner image from the intermediate transfer belt 302 to a sheet, and is pressed against the support roller 318 via the intermediate transfer belt 302. ing.

  In addition, the transfer device 300 includes a cleaning device 394. The cleaning device 394 cleans the intermediate transfer belt 302 by removing the toner remaining on the surface of the intermediate transfer belt 302 after the toner image is transferred onto the sheet by the secondary transfer roller 390.

  The paper feeding device 400 is a device that supplies paper to the conveyance path 600, and includes a storage container 402 that stores the paper so as to be stacked, and an uppermost sheet among the paper stacked in the storage container 402. A delivery roller 404 that feeds a certain sheet to the conveyance path 600 is provided.

  The transport path 600 is a transport path for transporting paper from the paper feeding device 400 to the discharge tray 16, and the above-described delivery roller 404 and transport in order from the upstream side in the paper transport direction along the transport path 600. A roller 610, a conveyance roller 612, a conveyance roller 710 and a driven roller 720, a registration roller 700, the above-described support roller 318 and secondary transfer roller 390, a conveyance device 620, a conveyance device 630, and a fixing device 180. Is arranged.

  The transport roller 710 is disposed upstream of the registration rollers in the paper transport direction, and is used as a supply member that supplies the paper toward the registration rollers 700. The driven roller 720 is disposed so as to sandwich the sheet with the conveyance roller 710 and is used as a driven member that is driven by the conveyance roller 710.

  In the stopped state, the registration roller 700 once stops the movement of the leading end of the sheet being sent out toward the downstream side in the transport direction by the transport roller 710, and the image forming unit 110Y, the image forming unit 110M, and the image forming unit The toner image formed by the unit 110C and the image forming unit 110K and transferred to the intermediate transfer belt 302 by the primary transfer roller 330Y, the primary transfer roller 330M, the primary transfer roller 330C, and the primary transfer roller 330K is the secondary transfer roller 390. And the intermediate transfer belt 302 is used as a conveying member that conveys the sheet so as to resume the movement of the leading end of the sheet so as to coincide with the timing of reaching the contact portion. Details of the registration roller 700, the conveyance roller 710, and the driven roller 720 will be described later.

  The conveying device 620 and the conveying device 630 transfer a sheet of paper in which the toner image is transferred to the upper surface in the gravity direction and the unfixed toner image is placed on the upper surface in the gravity direction from the lower side in the gravity direction. It is conveyed toward the fixing device 180 while being supported. The fixing device 180 uses, for example, heat and pressure to fix the toner image placed on the upper surface of the paper on the upward surface of the paper.

  FIG. 2 shows an image forming unit 110Y, an image forming unit 110M, an image forming unit 110C, and an image forming unit 110K. The image forming unit 110Y, the image forming unit 110M, the image forming unit 110C, and the image forming unit 110K have the same configuration although the color of the toner to be used and the color of the toner image to be formed are different. Therefore, these image forming units will be collectively referred to as the image forming unit 110 below. 2 shows a primary transfer roller 330Y, a primary transfer roller 330M, a primary transfer roller 330C, and a primary transfer roller 330K. Since the primary transfer roller 330M, the primary transfer roller 330C, and the primary transfer roller 330K have the same configuration, these primary transfer rollers will be collectively referred to as the primary transfer roller 330 below.

  As shown in FIG. 2, the image forming unit 110 makes the surface of the photosensitive drum 112 uniform before forming the latent image on the photosensitive drum 112 by the optical drum 260 and the optical drum 260 described above. A charging device 120 for charging the toner and a toner image forming unit for forming a toner image on the photosensitive drum 112. The latent image formed on the surface of the photosensitive drum 112 by the optical scanning device 260 is used with toner. The developing device 130 for developing and the surface of the photosensitive drum 112 are cleaned, and the toner remaining on the surface of the photosensitive drum 112 after the transfer of the toner image onto the intermediate transfer belt 302 by the primary transfer roller 330 is completed is removed. Device 140.

  FIG. 3 shows a registration roller 700, a conveyance roller 710, and a driven roller 720. As shown in FIG. 3, the image forming apparatus 10 includes a contact roller 730 disposed so as to contact the registration roller 700. The contact roller 730 rotates so as to be driven by the registration roller 700, sandwiches the sheet between the registration roller 700, and rotates in the direction of the arrow shown in FIG.

  For example, a drive source 744 such as a motor is connected to the registration roller 700 via a drive transmission mechanism 740 including a gear train and a clutch device 742 including an electromagnetic clutch. The clutch device 742 is controlled by the output from the controller 20 (see FIG. 1), transmits the drive from the drive source 744 to the registration roller 700, and cuts off the drive transmission from the drive source 744 to the registration roller 700. . A drive source 744 is connected to the transport roller 710 via a drive transmission mechanism 746 formed of, for example, a gear train. The registration roller 700 and the conveyance roller 710 can be rotated in a direction indicated by an arrow in FIG. 3 when driving is transmitted from a driving source 744.

  As described above, the registration roller 700 once stops the movement of the leading edge of the sheet that is being sent toward the downstream side in the transport direction by the transport roller 710. For this reason, as shown in FIG. 3, the sheet P is bent (looped), for example, downward (attitude) at a position between the conveyance roller 710 and the driven roller 720, the registration roller 700, and the contact roller 730. )

  The bending of the sheet P is caused by setting the peripheral speed of the transport roller 710 and the registration roller 700, for example, by setting the peripheral speed of the transport roller 710 and the registration roller 700 to be the same. It is maintained from the time when it passes through the contact portion between the roller 700 and the contact roller 730 to the time when the rear end portion of the paper P passes through the contact portion between the transport roller 710 and the driven roller 720. The peripheral speed of the conveying roller 710 can be set to a desired value by determining the reduction ratio of the drive transmission mechanism 746, and the peripheral speed of the registration roller 700 is set to a desired value by determining the reduction ratio of the drive transmission mechanism 740. be able to.

  As shown in FIG. 3, the image forming apparatus 10 has a posture in which the paper P is bent when the rear end portion of the paper passes through the contact portion between the conveyance roller 710 and the driven roller 720. Posture maintaining means 770 for maintaining the above. In the first embodiment, the posture maintaining unit 770 includes a separation member 772 that separates the rear end portion of the sheet P from the driven roller 720. The separation member 772 is made of, for example, a claw-like member or the like, and is arranged so that one end side contacts the driven roller 720. Instead of arranging the separating member 772 so that one end side contacts the driven roller 720, the separating member 772 may be arranged so that the one end side is in the vicinity of the driven roller 720 and is separated from the driven roller 720. good.

  The separation member 772 separates the paper P from the driven roller 720 so that the rear end portion of the paper P rides on the separation member 772. Since the trailing edge of the sheet P is separated from the driven roller 720 by the separation member 772, the trailing edge of the sheet P does not move with the driven roller 720 while being attracted to the driven roller 720. Is moved together with the driven roller 720, so that a situation in which the bent posture formed on the paper P is not maintained is less likely to occur.

  In this embodiment, the case where the deflection of the paper P is formed on the driven roller 720 side has been described. However, the deflection of the paper P may be formed on the conveyance roller 710 side. Whether the sheet P bends on the driven roller 720 side or on the transport roller 710 side depends on, for example, the surface material of the driven roller 720 and the material of the transport roller 710. It is usually determined on one side depending on whether one of them easily adsorbs the paper P or a position where a guide member (not shown) for guiding the paper P being conveyed is provided.

  When the deflection of the sheet P is formed on the conveyance roller 710 side, the separation member 772 is replaced with the separation member 772 so that one end side is in contact with the driven roller 720 or one end side is positioned in the vicinity of the driven roller 720. 772 is provided so that one end side contacts the conveyance roller 710 or one end side is positioned in the vicinity of the conveyance roller 710.

  A separation member 772 is provided so that one end side is in contact with the driven roller 720 or one end side is in the vicinity of the driven roller 720, or one end side is in contact with the transport roller 710 or one end side is in the vicinity of the transport roller 710. Instead of providing a separation member, one separation member 772 is provided so that one end side is in contact with the driven roller 720 or one end side is positioned in the vicinity of the driven roller 720, and one end side is in contact with the conveyance roller 710. Alternatively, another one separation member may be provided so that one end side is positioned in the vicinity of the conveyance roller 710. As described above, if the two separation members 772 are provided, even if the deflection of the paper P occurs on the opposite side to the assumed side, the bent posture formed on the paper P cannot be maintained. It becomes difficult to occur.

  4 and 5 show an enlarged part of the image forming apparatus 10 according to the second exemplary embodiment of the present invention. FIG. 4 is a view showing the same position as FIG. 3 in the drawing showing the first embodiment of the present invention, and FIG. 5 is a schematic view of the configuration seen from the direction of arrow AA in FIG. It is the figure shown in. In the following description, parts of the image forming apparatus 10 according to the second embodiment that are different from the image forming apparatus 10 according to the first embodiment will be described, and the image according to the first embodiment will be described. A description of the same parts as those of the forming apparatus 10 will be omitted.

  As shown in FIG. 5, the transport roller 710 includes a shaft portion 712 and, for example, two main body portions 714 attached to the shaft portion 712. The two main body portions 714 are disposed so as to be separated from each other in the longitudinal direction of the shaft portion 712. In the transport roller 710, the shaft portion 712 and the two main body portions 714 rotate as a unit.

  In the image forming apparatus 10 according to the first embodiment described above, the separation member 772 is included as the posture maintaining unit 770. On the other hand, in the image forming apparatus 10 according to the second embodiment, the posture maintaining unit 770 is driven when the rear end portion of the sheet P passes through the contact portion between the transport roller 710 and the driven roller 720. A stop mechanism 774 for stopping the roller 720 is provided.

  In the image forming apparatus 10 according to the first embodiment described above, the drive from the drive source 744 is transmitted to the transport roller 710 via the drive transmission mechanism 746. In contrast, in the image forming apparatus 10 according to the second embodiment, the drive from the drive source 744 is transmitted to the transport roller 710 via the drive transmission mechanism 746 and the clutch device 748. The clutch device 748 is controlled by the output from the controller 20 (see FIG. 1), transmits the drive from the drive source 744 to the transport roller 710, and disconnects the drive transmission from the drive source 744 to the transport roller 710. .

  In addition, the image forming apparatus 10 according to the second embodiment includes a trailing edge detection sensor 752 that detects that the trailing edge of the sheet P has passed a position where the conveying roller 710 and the driven roller 720 are in contact with each other. ing. The output from the rear end detection sensor 752 is input to the controller 20 (see FIG. 1).

  FIG. 6 schematically shows the configuration of the stop mechanism 774. As shown in FIG. 6, the stop mechanism 774 includes a rotating plate 776 connected to the shaft portion 722 of the driven roller 720 and a pressing plate 778 pressed against the rotating plate 776. By being controlled by the controller 20, when the pressing plate 778 moves from the position shown in FIG. 6 and is pressed against the rotating plate 776, the rotation of the driven roller 720 is stopped.

  FIG. 7 illustrates the operation of the image forming apparatus 10 according to the second exemplary embodiment of the present invention. In the process of forming an image on the paper P, a series of controls shown in FIG. As shown in FIG. 7, when the trailing edge detection sensor 752 detects that the trailing edge of the sheet has passed through the contact portion between the transport roller 710 and the driven roller 720 in step S10, the controller in step S20. 20 activates the stop mechanism 774 to press the pressing plate 778 against the rotating plate 776 to stop the rotation of the driven roller 720. In step S20, it is desirable to control the clutch device 748 to cut off the transmission of drive from the drive source 744 to the conveyance roller 710.

  In the image forming apparatus 10 according to the second embodiment, when the trailing edge detection sensor 752 detects that the trailing edge of the sheet has passed through the contact portion between the transport roller 710 and the driven roller 720, the stop mechanism 774 stops the driven roller 720. For this reason, the driven roller 720 does not continue to rotate with the trailing edge of the paper P adsorbed to the driven roller 720, and the driven roller 720 continues to rotate, so that the bent posture formed on the paper P is maintained. The situation that it will not be done is less likely to occur.

  In this embodiment, the case where the deflection of the paper P is formed on the driven roller 720 side has been described. However, the deflection of the paper P may be formed on the transport roller 710 side as described above. When the deflection of the sheet P is formed on the transport roller 710 side, a stop mechanism 774 is provided to stop the transport roller 710 instead of providing the stop mechanism 774 to stop the driven roller 720.

  Instead of providing a stop mechanism 774 to stop the driven roller 720 or a stop mechanism 774 to stop the transport roller 710, a single stop mechanism 774 is provided to stop the driven roller 720 and transport Another stop mechanism 774 may be provided to stop the roller 710. As described above, if two stop mechanisms 774 are provided, even if the deflection of the paper P occurs on the opposite side to the assumed side, the bent posture formed on the paper P may not be maintained. It becomes difficult to occur.

  In the above description, instead of the posture maintaining unit 770 having the separation member 772 included in the image forming apparatus 10 according to the first embodiment, the posture maintaining unit 770 includes the stop mechanism 774. However, the image forming apparatus 10 may be configured such that the posture maintaining unit 770 includes both the separation member 772 and the stop mechanism 774.

  FIG. 8 is an enlarged view of a part of the image forming apparatus 10 according to the third embodiment of the present invention, and the same position as FIG. 3 in the diagram showing the first embodiment of the present invention described above. FIG. In the following description, parts of the image forming apparatus 10 according to the third embodiment that are different from the image forming apparatus 10 according to the first embodiment described above will be described, and the image according to the first embodiment described above will be described. The description about the same part as the forming apparatus 10 is omitted.

  The image forming apparatus 10 according to the first embodiment described above has the separation member 772 as the posture maintaining unit 770, and the image forming apparatus 10 according to the second embodiment described above as the posture maintaining unit 770 as a stop mechanism 774. Had. On the other hand, the image forming apparatus 10 according to the third embodiment includes a friction system coefficient reducing unit that reduces the friction coefficient of the surface of the driven roller 720 as the attitude maintaining unit 770. More specifically, A coating 726 made of, for example, polytetrafluoroethylene (PTFE) is applied on the surface of the driven roller 720.

  In the image forming apparatus 10 according to the third embodiment, the trailing edge of the sheet that has passed through the contact portion between the transport roller 710 and the driven roller 720 is compared to the case where the coating 726 is not applied. Easy to move away from. For this reason, it is difficult for the rear end of the paper P to move with the driven roller 720 in a state where the rear end of the paper P is attracted to the driven roller 720, and the rear end of the paper P moves with the driven roller 720 to form the paper P. It is difficult to cause a situation where the bent posture is not maintained.

  In this embodiment, the case where the deflection of the paper P is formed on the driven roller 720 side has been described. However, the deflection of the paper P may be formed on the transport roller 710 side as described above. In such a case, if the conveyance roller 710 is coated to correspond to the coating 726 in order to maintain the deflection of the paper P, the surface friction coefficient is reduced, so that the conveyance roller 710 can convey the paper well. Disappear. For this reason, the conveyance roller 710 cannot be coated corresponding to the coating 726. When the deflection of the paper P is formed on the conveyance roller 710 side, the conveyance roller 710 is not coated, but the above-described separation is performed. A member 772 (see FIG. 3) is arranged on the conveying roller 710 side, or the aforementioned stop mechanism 774 (see FIG. 4) is provided to stop the driving of the conveying roller 710.

  In the above description, the attitude maintaining unit 770 is replaced with the separation member 772 included in the image forming apparatus 10 according to the above-described first embodiment, or the image according to the above-described second embodiment. Although the example in which the coating 726 is performed instead of having the stop mechanism 774 that the forming apparatus has has been described, the posture maintaining means 770 includes both the separation member 772 and the coating 726, or the stop mechanism 774. You may make it have both the coating 726. Further, the posture maintaining means 770 may include all of the separation member 772, the stop mechanism 774, and the coating 726.

  FIG. 9 is a first diagram illustrating the state of the sheet in the image forming apparatus according to the comparative example of the present invention. FIG. 9A illustrates the contact portion between the supply roller and the driven roller at the rear end of the sheet. FIG. 9B shows the state of the paper after a predetermined time has elapsed from the time shown in FIG. 9A.

  Each of the image forming apparatuses 10 according to the first embodiment, the second embodiment, and the third embodiment described above has the posture maintaining means 770. On the other hand, the image forming apparatus 10 according to this comparative example does not have the posture maintaining unit 770. Further, in the image forming apparatus 10 according to this comparative example, as the driven roller 720, a roller on which a material that easily adsorbs paper P such as rubber is used is used.

  In the image forming apparatus 10 according to the comparative example, the rear end portion of the paper P that has passed through the contact portion between the transport roller 710 and the driven roller 720 is not separated from the driven roller 720 and is attracted to the driven roller 720. With the rotation of the driven roller 720, for example, the rear end of the paper P may move to the position indicated by the solid line in FIG.

  9A, when the trailing end of the paper P is separated from the driven roller 720, the paper P is, for example, as shown in FIG. 9B due to the rigidity of the paper P (the stiffness of the paper P). It moves to the position indicated by the two-dot chain line, and then moves to the position indicated by the solid line in FIG. Then, when the paper P moves to the position indicated by the solid line in FIG. 9B, the rear end portion of the paper P collides with the driven roller 720, and a sound is generated at the time of the collision.

  FIG. 10 is a second view for explaining the state of the sheet in the image forming apparatus according to the comparative example of the present invention. FIG. 10A shows the contact portion between the supply roller and the driven roller at the rear end of the sheet. FIG. 10B shows the state of the paper after a predetermined time has elapsed from the time shown in FIG. 10A.

  In the image forming apparatus 10 according to the comparative example, the rear end portion of the paper P that has passed through the contact portion between the transport roller 710 and the driven roller 720 is not separated from the driven roller 720 and is attracted to the driven roller 720. With the rotation of the driven roller 720, for example, the rear end of the paper P may move to the position indicated by the solid line in FIG.

  When the trailing end of the paper P is separated from the driven roller 720 at the position indicated by the solid line in FIG. 10A, the paper P is, for example, as shown in FIG. 10B due to the rigidity of the paper P (the stiffness of the paper P). It moves to the position indicated by the two-dot chain line, and then moves to the position indicated by the solid line in FIG. When the paper P moves to the position indicated by the solid line in FIG. 10B, the rear end portion of the paper P collides with the transport roller 710, and a sound is generated at the time of the collision.

  As described above, the present invention can be used for an image forming apparatus such as a copying machine, a facsimile apparatus, and a printer, and for example, a conveyance device used in these image forming apparatuses.

DESCRIPTION OF SYMBOLS 10 ... Image forming apparatus 20 ... Controller 100 ... Image forming part 700 ... Registration roller 710 ... Conveyance roller 720 ... Driven roller 726 ... Coating 742 ... Clutch device 744 ..Drive source 748 ... Clutch device 752 ... Rear end detection sensor 770 ... Attitude maintaining means 772 ... Separating member 774 ... Stop mechanism 776 ... Rotating plate 778 ... Pressing plate

Claims (5)

A transport member that transports the transport target object by stopping the front end part of the transport target object in a state where the rotation is stopped, and restarting the movement of the front end part of the transport target object by starting rotation;
A supply member that is disposed upstream of the transport member in the transport direction of the transport object and that supplies the transport object toward the transport member;
A driven member that is disposed so as to sandwich a conveyance object with the supply member, and is driven by the supply member;
Deflection formed in the conveyance object at a position between the supply member and the driven member and the conveyance member when the rear end of the conveyance object passes through the contact portion between the supply member and the driven member Attitude maintaining means for maintaining the object to be conveyed in an attitude having
Conveying device having   The transport apparatus according to claim 1, wherein the posture maintaining unit includes at least one of a separation member that separates the conveyance target from the driven member and a separation member that separates the conveyance target from the supply member.   The posture maintaining means includes stop means for stopping at least one of the driven member and the supply member when a rear end portion of the conveyance object passes through a contact portion between the supply member and the driven member. Item 3. The conveying apparatus according to Item 1 or 2.   The conveying apparatus according to claim 1, wherein the posture maintaining unit includes a friction coefficient reducing unit that reduces a friction coefficient of the surface of the driven member. An image forming unit for forming an image on a recording medium;
A conveyance member that conveys the recording medium by stopping the leading end of the recording medium in a state where the rotation is stopped and restarting the movement of the leading end of the recording medium toward the image forming unit;
A supply member that is disposed upstream of the transport member in the transport direction of the recording medium and that supplies the recording medium toward the transport member;
A driven member that is disposed so as to sandwich a recording medium between the supply member and follows the supply member;
Deflection formed in the conveyance object at a position between the supply member and the driven member and the conveyance member when the rear end of the conveyance object passes through the contact portion between the supply member and the driven member Attitude maintaining means for maintaining the conveyance object to maintain an attitude having
An image forming apparatus.

Images